This invention relates to a hose clamp capable of tightening without stripping, yet having a low cost of manufacture.
Hose clamps of a variety of types have been devised previously. One difficulty with known hose clamps is that of stripping if slightly excessive tightening force is applied. It is important to fully tighten the clamp to prevent leakage, but a slight overtightening can result in clamp failure. To counteract this, some hose clamps have been formed with a nut secured adjacent one of the clamp ears for engagement with a plurality of threads on the tightening screw. Unfortunately, making and mounting a nut on the clamp is costly. Efforts to eliminate the nut have led to special folded tabs as, for example, in U.S. Pat. Nos. 4,246,690; 4,078,281; and 4,310,956. One proposal shown in FIG. 7 of U.S. Pat. No. 4,246,690 and its related patents noted above has a simple extension of the strip protruding tangentially from the remainder of the strip for engagement of a couple turns of the screw threads. Other variations are set forth in U.S. Pat. Nos. 2,423,627 and 1,479,317. Providing the multiple folded structure adds cost to the product and too often does not eliminate the stripping problem. A third type of clamp uses a worm drive action of the screw threads with a plurality of transverse slots specially formed in the band. The band is made of hard, high quality steel to withstand the force of the worm drive. These features add considerable production cost.